The present subject matter relates generally to a rocket launch tower having pre-acceleration of the rocket before powered flight. More specifically, the present invention relates to a rocket launch tower that uses falling counterweights to accelerate and stabilize a platform supporting a rocket at a higher rate of speed than the speed of the counterweights.
Launching rockets into space is very energy intensive and inefficient. Modern launch vehicles are able to deliver between 1% (Space Shuttle) and at most 4% (Saturn V) of the total vehicle mass at launch into low earth orbit. This makes it extremely costly to deliver even a small payload to space (going rates are $5000-$10,000 per kilogram). A number of inventions have been proposed to provide ground-based power for helping to launch rockets but so far none have been implemented successfully.
One previously proposed solution involves using falling counterweights with a simple fixed pulley arrangement to accelerate a rocket upward (See, for example, U.S. Pat. Nos. 3,088,698 and 7,530,532). Using this solution, the greatest acceleration a falling object can achieve is 1 g. A counterweight using a simple fixed pulley that is lifting a load will always accelerate at less than 1 g. Therefore, a simple pulley lifting a rocket launch platform will accelerate a rocket at less that 1 g. As a traditional rocket already accelerates upward at around 0.5 g such a counterweight launch arrangement does not provide much benefit, or requires an extremely tall tower structure.
Another previously proposed solution involves recirculating exhaust gas from a rocket to push a launch platform upward (See, for example, U.S. Pat. Nos. 3,363,508 and 6,318,229). Containing recirculated exhaust gas requires either a chamber sealed to the engines of the rocket (which is technically complicated and prone to damage the engines due to backpressure) or an unsealed or partially sealed chamber that would provide inconsistent pressure and therefore inconsistent acceleration of the rocket.
A further previously proposed solution involves using electric motors to pull cables that accelerate a rocket upward (See, for example, U.S. Pat. No. 3,363,508). Electric motors to propel a rocket would be excessively large and require an excessive amount of energy at launch—this is technically difficult and expensive to achieve.
Yet another previously proposed solution involves using a compressed gas to rapidly inflate a chamber underneath a rocket, propelling it upwards (U.S. Pat. No. 6,354,182). Propelling a rocket using an expanding gas requires a sealed chamber under the rocket that remains sealed as the rocket accelerates upward. Such a large sealed chamber (like a giant gun barrel) is impractical and excessively expensive to manufacture for the size necessary, and the machinery necessary to smoothly but powerfully fill this giant cylindrical barrel would be excessively large, complex, and expensive.
An even further previously proposed solution involves stretching elastic material under a rocket and using it to propel a rocket upward (See, for example, U.S. Pat. No. 6,354,182). No such material exists that will contain sufficient energy over a sufficient range of motion to make an elastic launch system useful or practical.
Moreover, none of the existing rocket launch mechanisms provide the capacity to finely adjust and control the upward acceleration in the range appropriate and useful for a rocket. Too much acceleration (over about 5 g) will damage the rocket, and too little will not provide enough assistance to guarantee the rocket reaches orbit with its additional payload. It is important that the upward acceleration can be finely controlled in the useful range for a rocket.
Additionally, none of the existing rocket launch mechanisms guarantee that the rocket will be accelerated in a straight line, with no tilting or lateral movement (movement perpendicular to the centerline of the rocket). Rockets are relatively fragile in all directions excepting a steady push from below, and any system that does not provide for a smooth enough, straight vertical acceleration is prone to damage the rocket.
Finally, prior attempts failed to take into account the limited acceleration provided by a simple (non-multiplying) pulley arrangement, as well as the need to precisely control the acceleration as well as lateral and tilting movement of the launch platform. In the absence of these features, a gravity-powered launch tower would not be useful. As evidence, none was ever built.
What is needed are mechanisms to address the weaknesses in current launch technology and substantially improve the payload capacity of existing and future rockets for relatively low cost.
Accordingly, there is a need for a rocket launch tower including a pulley system that drives a platform that is dynamically stabilized, as described herein.